RIVERSIDE (CNS) – Temperatures in the Coachella Valley are expected to hit triple digits today, and the mercury throughout Riverside County will be on the rise all week, according to the National Weather Service.

Conditions west of the Coachella Valley will be relatively mild today, but building high pressure will cause temperatures to rise throughout the county until Friday, forecasters said. By midweek, high temperatures could be 15-20 degrees above average in most areas, forecasters said.

The NWS issued a heat advisory that will be in effect from 10 a.m. Tuesday to 9 p.m. Friday in the Riverside metropolitan area. An excessive heat watch will also take effect Tuesday morning and last until Friday evening in the Coachella Valley and the San Gorgonio Pass.

The NWS urged residents to drink plenty of fluids, stay out of the sun and check up on relatives and neighbors.

Also, young children and pets should be never be left unattended in a vehicle, with car interiors able to “reach lethal temperatures in a matter of minutes,” according to the NWS.

High temperatures today are forecast to reach 100 in the Coachella Valley, 89 in the San Gorgonio Pass near Banning, 89 in Hemet and Riverside, 87 in Lake Elsinore, 84 in Temecula and 76 in Idyllwild.

High temperatures in the Riverside metropolitan area are expected to top out in the mid- to high-90s on Wednesday and Thursday, while the mercury in the Coachella Valley is expected to reach its peak at 107 on Thursday, forecasters said.